It's tough to systematically compare religious faith with ordinary cognition, so calibrate accordingly, but in a neuroimaging study the researchers found that while the human brain responded very differently to religious and nonreligious propositions, the process of believing or disbelieving a statement, whether religious or not, was governed by the same areas in the brain.
So believing in God or believing the sun is a star takes the same belief, or suspension of disbelief, at the brain level, they say. The study also found that devout Christians and nonbelievers use the same brain regions to judge the truth of religious and nonreligious propositions.
The study involved 30 adults — 15 committed Christians and 15 nonbelievers — who underwent three functional MRI (fMRI) scans while evaluating religious and nonreligious statements as "true" or "false." The statements were designed to produce near perfect agreement between the two groups during nonreligious trials (e.g., "Eagles really exist") and near perfect disagreement during religious trials (e.g., "Angels really exist").
Contrasting belief and disbelief yielded increased activity in the ventromedial prefrontal cortex (VMPFC), an area of the brain thought to be involved in reward and in judgments of self-relevance.
"This region showed greater activity whether subjects believed statements about God, the Virgin Birth, etc., or statements about ordinary facts," the authors said.
The case for belief being content-independent was further bolstered by the fact that while the trial statements accepted by religious believers were rejected by nonbelievers, and vice versa, the brains of both showed the same pattern of activity for belief and disbelief.
A comparison of all religious with all nonreligious statements suggested that religious thinking is more associated with brain regions that govern emotion, self-representation and cognitive conflict in both believers and nonbelievers, while thinking about ordinary facts is more reliant upon memory retrieval networks. Activity in the brain's anterior cingulate cortex, an area associated with cognitive conflict and uncertainty, suggested that both believers and nonbelievers experienced greater uncertainty when evaluating religious statements.
The study raises the possibility that the differences between belief and disbelief may one day be reliably distinguished by neuroimaging techniques.
"Despite vast differences in the underlying processing responsible for religious and nonreligious modes of thought," the authors write, "the distinction between believing and disbelieving a proposition appears to transcend content. These results may have many areas of application — ranging from the neuropsychology of religion, to the use of 'belief-detection' as a surrogate for 'lie-detection,' to understanding how the practice of science itself, and truth-claims generally, emerge from the biology of the human brain."
The authors report no conflict of interest. Work in Dr. Cohen's lab is funded by grants from the National Institutes of Health.
Citation: Harris S, Kaplan JT, Curiel A, Bookheimer SY, Iacoboni M, et al. (2009) The Neural Correlates of Religious and Nonreligious Belief. PLoS ONE 4(10): e7272. doi:10.1371/journal.pone.0007272